The present invention relates generally to vehicle power shift transmissions and more particularly to a planetary transmission which is capable of being shifted between six forward speeds and two reverse speeds.
In the past, a relatively complex system for gears, brakes, and clutches were required in order to provide a large number of speed ratios as shown in the U.S. Pat. No. 3,298,252 granted to K. J. Harris et al which provided eight forward and four reverse speeds. With further development fo planetary transmissions, simple arrangements have been devised such as that shown in the U.S. Pat. No. 3,381,546 granted to H. H. Holl; however, with simplification, the number of speed ratios has been decreased, for example with the Holl transmission only four forward and three reverse speeds are available.